Manuzal device for ejecting burs from dental handpieces



July 30, 1968 BLACK 3,394,449

MANUAL DEVICE FOR EJECTING BURS FROM DENTAL HANDPIECES Filed Oct. 10, 1965 United States Patent 3,394,449 MANUAL DEVICE FOR EJECTING BURS FROM DENTAL HANDPIECES Robert L. Black, Corpus Christi, Tex., assignor to Robert B. Black, Corpus Christi, Tex. Filed Oct. 10, 1966, Ser. No. 585,492 1 Claim. (Cl. 29278) ABSTRACT OF THE DISCLOSURE A device for ejecting burs from the head of a dental handpiece, the device comprising a body having a bore with a plunger reciprocable therein and projecting from one end of the bore, a yoke projecting from the body at the other end of the bore to receive the head of a dental handpiece, with the bur projecting over and beyond the remote end of the yoke and a bur ejecting pin connected with the plunger and adapted to enter the chuck of the head behind the bur in order to eject the bur from the chuck.

This invention is concerned with equipment for use in ejection of burs or other rotary tools from the chuck provided in the head of a dental handpiece.

With many forms of dental drilling equipment, the bur or other rotary tool is received in a friction chuck which is rotatively mounted Within the head of the handpiece, and considerable force is required to eject the burs from such friction clutches. In consequence, ejection of the burs has sometimes resulted in injury to the dentists hands or fingers, and sometimes has also resulted in damage to the handpiece, ejector or to the chuck.

The principal object of the present invention is the provision of a bur ejector comprising a manually operated device which is of simple construction and is easy to operate, without danger of injury to the fingers or to the dental handpiece itself.

It is also an object of the invention to provide a manually operable device of the kind referred to which not only accomplishes the foregoing objects but which also is arranged to provide for the development of a very substantial bur ejecting force, notwithstanding the fact that the device is arranged for manual operation.

Still another object of the invention is to provide an arrangement facilitating centering or properly positioning the bur ejecting element with respect to the chuck, even when the bur ejecting device is employed with handpieces of which the heads or chucks are of different sizes.

How the foregoing objects and advantages are obtained, together with others which will occur to those skilled in the art, will be clear from the following description referring to the accompanying drawing, in which- FIGURE 1 is a perspective view of a manual bur ejecting device of the present invention, the device being here shown as being held in the hands of a user, in accordance with the intended mode of operation;

FIGURE 2 is a longitudinal sectional view through the device shown in FIGURE 1 and illustrating also, in axial section, certain parts of the head of a dental handpiece of the type with which the ejector is adapted to be employed; and

FIGURE 3 is an elevational view taken from the left of FIGURE 2.

Referring to the drawing, the device of the invention comprises a body 4 having a bore 5 therein in which the plunger 6 is reciprocable. The plunger 6 has a bur ejectitng pin 7 secured therein and projecting (toward the left as viewed in FIGURES l and 2) into the space within the extension arm or yoke 8, one end wall 9 of which has a threaded connection 10 with the body 4 and is apertured "ice to pass the pin 7. The portion of the wall 9- surrounding the aperture for the pin 7 thus serves as a guide for the pin. The yoke 8 also has a wall 11 spaced from the wall 9 to accommodate the head of a dental handpiece, the head being generally indicated at 12 and a part of the handpiece itself being shown at 13 in FIGURE 1. The upper edge of the wall 11 is bifurcated as indicated at 14 thus forming a cradle for receiving the bur or other rotary tool, such as indicated at 15, which projects from the handpiece head 12. The bifurcated upper portions of the wall 11 project into the space between the parts 9 and 11 in order to provide an abutment against which the end surface of the head 12 may contact during the application of the bur ejecting force.

From FIGURE 2 it will be seen that there is clearance between the parts 9 and 11 of the yoke beyond that required to exactly accommodate the head 12 of the handpiece, and further that the lower part of the yoke 8 is offset downwardly sufficiently to provide clearance below the head 12. This is desired in order to accommodate handpiece heads of different sizes.

The helical spring 16 surrounding the outer end portion of the plunger 6 acts against the body 4 and the shank 17 of the hand operating knob 18, in order to urge the plunger and the pin 7 to the right as viewed in FIGURES 1 and 2, i.e. in order to retract the pin 7 from the yoke space. The knob 18 serves as the actuating element for advancing the plunger 6 and the ejecting pin 7. The action of the spring 16 in moving the plunger 6 to the right is limited by a set screw 6a the inner end of which is received in a groove formed in the plunger 6, the righthand end of the wall of the groove serving as a stop, as appears in FIGURE 2.

A pair of arcuate finger engaging elements 19 project at opposite sides of the device, being mounted by means of a sleeve 20 on the body 4. As seen in FIGURE 1, the device is adapted to be grasped by placing the index and the middle fingers of the hand over the arcuate elements 19 and by placing the actuating knob 18 in the palm of the hand, preferably in the region adjacent to the base of the thumb. In this way, a very substantial bur ejecting force may be manually developed by a simple squeezing motion of the hand.

The illustration of the head 12 of the handpiece in FIGURE 2 shows the bearings 21 which serve to rotatively mount the sleeve 22 in which a friction clutch is customarily arranged in order to receive the shank of the bur 15 or other rotary tool adapted to be mounted in the friction clutch of the head. The sleeve 22 and thus the chuck and the bur therein are adapted to be driven by mechanism which need not be considered herein since it forms no part of the present invention per se. Such drive mechanism may comprise a turbine device between the spaced bearings 2121.

When used in the manner illustrated in the drawing the head of the handpiece is first placed into the yoke space at an inclined angle so that the end of the ejecting pin 7, which projects beyond the surface of the part 9 enters the opening in the chuck behind the shank of the bur 15. The head of the handpiece is then turned downwardly until the bur rests in the cradle 14, and at this time the head is held adjacent to the surface of the part 9, so that the entire head is centered in the ejecting device by virtue of the pin 7 engaging in the chuck and by the bur 15 resting in the cradle 14.

After the head is thus positioned in the device, the hand knob 18 is actuated, thereby shifting the handpiece head to the left until it abuts the inner edges of the bifurcated part 14. Increasing the hand pressure will then advance the pin 7 into the head behind the shank of the bur 15 and forces the but from the chuck.

Ejection of a bur in this manner may readily be accomplished without danger of puncturing a finger or damaging a hand, and the ready portability of the device facilitates its use in ejecting a bur at any desired point, for instance onto the customary instrument tray.

I claim:

1. A device for ejecting a bur from the chuck in the head of the hand piece of a dental drill, comprising a body having a bore extended therethrough, a plunger reciprocable in said bore and projecting from the 'body at one end of the bore, a yoke projecting from the body at the other end of the bore, the yoke being shaped to receive the chuck of a dental drill with the axis of the chuck in alignment with the bore in the body and with the bur in the chuck projecting in a direction away from the body and over and beyond the remote end of the yoke, a bur ejecting pin connected with the plunger and extended therefrom toward the yoke in position to enter the chuck behind the 'bur therein, the yoke being sufficiently large to provide clearance radially of the chuck, in order to accommodate alignment of hand piece heads of different sizes, and the remote end of the yoke having a cradle for receiving the projecting end of a bur to be ejected from said chuck, the base of said cradle being spaced above the bottom of the yoke to support and align the bur with the ejecting pin, and mechanism for use in advancing the plunger in the'bore and thus the pin into the yoke to forcibly eject the bur from the chuck received in the yoke, said mechanism comprising hand grip elements on the plunger and body adapted to be grasped between fingers and the palm of a hand for actuation of the plunger by a hand squeezing motion.

References Cited UNITED STATES PATENTS 837,577 12/1906 Loud 29257 X 1,478,555 12/1923 Dahm 29249 1,488,208 3/1924 Laplace et al. 29249 1,651,258 11/1927 Detfenbaugh 294-100 2,797,471 7/1957 Hamberger 29278 X 3,210,832 10/1965 Kalen 29278 X 3,222,766 12/1965 Camargo 29278 X 3,307,250 3/1967 Goodwin et al. 29257 FOREIGN PATENTS 647,647 7/1937 Germany.

MYRON C. KRUSE, Primary Examiner. 

